I'd like to be able to deconstruct `complex` objects into their real and imaginary components using a `match` statement, like: match 1-4j: case complex(a, b): print(f"{a=} {b=}") This would just require setting complex.__match_args__ = ("real", "imag") The other builtin type I think should be able to do this is `slice`: match slice(1, -1, None): case slice(start, stop, step): print(f"{start=} {stop=} {step=}") which would require slice.__match_args__ = ("start", "stop", "step") This would be useful, for example, in custom __getattr__ methods which need to handle slices. def __getattr__(self, arg): match arg: case slice(start, stop, end): ... # handle slice case n if isinstance(n, int): ... # handle single index case _: raise TypeError There are various other builtin types which could conceivably have __match_args__ defined, but with varying degrees of usefulness: range, property, staticmethod, classmethod, memoryview, types.GenericAlias, types.UnionType, types.CodeType, types.FunctionType, types.MethodType, types.ModuleType, types.GenericAlias, types.FrameType, types.TracebackType, types.CellType But none of these are really that important, I think. What do you think? Patrick